Scaling Physiologic Function from Cell to Tissue in Asthma, Cancer, and Development.

The formation of an integrated tissue from individual cells depends on the properties of the individual cells as well as the interaction of many cells acting as a collective. Three fundamental physiological processes govern the collective scaling from the individual cell to a working tissue: cell sorting, tissue assembly, and collective cellular migration. Mechanistically, cell sorting is governed by differential adhesion, whereas tissue assembly is controlled by the epithelial-to-mesenchymal transition and its inverse, the mesenchymal-to-epithelial transition. The mechanism driving collective cellular migration, however, is not clear. To fill that gap, here we consider cell jamming and unjamming, and their role in collective cellular migration.